Field of the Invention
The present invention relates to an image processing apparatus for determining a unique portion (an unusual portion including a defect) in a print image on the basis of data resulting from reading the print image.
Description of the Related Art
Japanese Patent Laid-Open No. 2013-185862 and ““KIZUKI” Algorithm inspired by Peripheral Vision and Involuntary Eye Movement”, Journal of the Japan Society for Precision Engineering, Vol. 79, No. 11, 2013, p. 1045-1049 discloses an algorism for detecting a defect of an inspection object in accordance with a human visual mechanism. Specifically, after imaging an inspection object, the resulting image is divided into division areas having a predetermined size, and a luminance value in each division area is averaged and quantized. In addition, such image processing is repeated using different sizes and/or phases of a division area, the resulting values quantized in the repeated image processing are added, and on the basis of the addition result a defect in the inspection object is detected. By employing such a method, a defect of an inspection object can be efficiently extracted and made apparent without any human observation.
However, when employing the algorithm disclosed in Japanese Patent Laid-Open No. 2013-185862 and “KIZUKI” Algorithm inspired by Peripheral Vision and Involuntary Eye Movement”, Journal of the Japan Society for Precision Engineering, Vol. 79, No. 11, 2013, p. 1045-1049, it is desirable to make various parameters such as the read resolution of an inspection object and the division size in image processing suitable in order to effectively detect a defect in the inspection object. For example, an image printed by an inkjet printing apparatus may have, as a unique portion, a stripe-like defect and density unevenness, and a read resolution and division size for effectively detecting these stripe-like defect and density unevenness vary depending on the features of the stripe-like defect and density unevenness. However, Japanese Patent Laid-Open No. 2013-185862 and “KIZUKI” Algorithm inspired by Peripheral Vision and Involuntary Eye Movement”, Journal of the Japan Society for Precision Engineering, Vol. 79, No. 11, 2013, p. 1045-1049 do not describe the relation between the feature of a defect to be detected and its corresponding suitable parameters.